Method of making and trimming ballast resistors and barrier metal in microwave power transistors
US5336631A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 26, 1993 |
| Grant date | Aug 9, 1994 |
| Priority date | — |
| Expiry date | May 26, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S148/136
Abstract
A method for fabricating microwave power transistor elements onto a semiconductor body. An oxidizable barrier material is applied onto the wafer that both acts as a barrier to prevent diffusion between the contact metal of the transistor and the silicon and also acts as a ballast resistor. A contact metal layer is then deposited onto the barrier material at selected locations and the excess barrier material is removed. Barrier material is left between the contact metal and the silicon and at the selected ballast resistor locations. The ballast resistors may then be trimmed, increasing the value of the resistors, by oxidizing a thin surface layer of the exposed barrier material at the ballast resistor locations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.